Processes of impregnating cellulosic fabrics



. Patented July 28, 1936 UNITED STATES PATENT CFFl-CE PROCESSES F IMPREGNATING CELLULOSIC FABRICS Pierre Meunier, Paris, France. assignor to Reslnes et Vernls Artiliclels (Societo Anonyme), Lyon, Rhone, France, a company of France No Drawlng. Application March 27, 1934, Serial in France March 31, 1933 I 6 Claims. (CI. 91-70) It has been known for a long time that various properties of fabrics of any kind and more especially cellulosic fabrics could be improved by im pregnating them with synthetic resins that are soluble and subsequently polymerizing these resins through the action of heat.

The first applications of this method were made with resins obtained by condensation of phenols with formaldehyde, by utilizing the so-called 10 bakelization process.

The same principle was applied by Ruff to the treatment of paper fabrics (German Patents No. 302,551 of July 6, 1917, No. 303,926 of March 21, 1917, No. 327,399 of October 27, 1917). More recently, the Tootal Broadhurst Company (British Patents :No. 291,473, 291,474 and 304,900) improved the method of Guntherby performing a preliminary mercerizing oi the fabric, and treating the product in a boiling soap bath after polymerization in order to facilitate, on the one hand, the penetration of the resin in the fibre and, on

the other hand, the elimination of the excess of phenol and of the soluble condensation products.

Other methods, including the impregnation of 85 fabrics of any kind whatever with phenolic synthetic resins have been proposed by Blumer (German Patent No. 174,745) and Bucherer (German Patent No. 339,301 of August 24, 1918) By treating cotton and artificial silk fabrics according to the method set forth in the German Patent No. 318,509 to Gunther, the stiffening produced on the fabric permits the easy fixation of the colouring materials and this stiffening is permanent, that is to say is not destroyed by washing and resists rumpling.

However, the utilization of formaldehyde and phenol resins permits the application of the method only in the case of dark shades because of the oxidation of the traces of phenol that are not combined under the influence of light, and of the alteration of the colors that results therefrom.

When synthetic resins other than phenol formaldehyde condensation products were discov- 5 ered, it was endeavoured to apply them to the impregnation of fabrics with a view to obtaining permanent stlileningcompounds having more or less interesting practical properties.

In the German Patent No. 556,393, filed in the name of the Cotton Treating Syndicate, which 5 ence of an acid agent.

This process, the principle of which is substantially the same as that of Gunther for phenolic resins, is chiefly intended to fix the filling ma- 15 terial's on the fabrics but it'produces, as the Gunther process, a permanent stiffening matter which resists washing and rumpling. However, this process has the disadvantage of being somewhat expensive, due to the utilization of thiourea.

I may also cite the German Patents No. 535,234 of October 6, 1926, and No. 537,036 of July 26, 1927, flied by the I. G. Farbenindustrie, concerncellulose. Drying is eiiected by means of solutions of dimethylol-urea with a view to reducing tfiek power of swelling of the threads of artificial s The British Patent No. 291,473, of December 1, 30

1926, teaches impregnating fabrics with soluble resins resulting from the condensation of arch-- nary urea with formaldehyde. The general process is very much the same as that disclosed by the Patents No. 318,509 (Gunther) and No. 556,- 393 (Cotton Treating Syndicate) however it includes a preliminary mercerizing in order to facilitate the penetration of the resin.

Fabrics treated according to the processes above mentioned have more or less different 40 qualities according to the nature of the resins that are utilized, the concentration of the resin solutions, etc., but they are permanently stiffened or dressed, that is to say they are capable of 45 resisting washing and rumpling.

For practical purposes use will be made of resins giving, to the maximum degree, the permanency of the stiffening (that is to. say the resistance to washing and rumpling), and the 50 properties of plasticity of the resins that are employed will play an important part.

One shall thus preferably utilize resins capable of preserving the original aspect and feel of the fabrics, as far as possible,'and which will have 66 ing the treatment of freshly precipitated hydro- 25 a great stability in-the state of solutions, in

order to facilitate their use.

pling while preserving the flexibility of the fabric and a good feel thereof. The resins that are utilized according-to the present invention have the further advantage that they necessitate no preliminary treatment of the fabrics (even in the case of cotton fabrics), =said fabrics being merely impregnated with the resin that is used and then subjected to a polymerizing treatment by means of. heat, in a manner similar to that taught by Gunther, either in the presence of a catalyst or not. They further possess the advantage of having a good stability when in solution.

The resins that are employed for the treatment of fabrics according to obtained by condensation of formaldehyde with ammonium sulphides or ammonium suiphocyanide, in the presence of variable quantities of urea, or by condensation of thioaldehydes with urea.

As a matter of fact, ammonium sulphide can combine with formaldehyde without disengagement of sulphuretted hydrogen so as to give com-.

pounds of the type of sulphines (pentamethylenediamine-disulphine and thialdines, Delepine, A. Ch. vol. 15. p. 570-574 and thesis 1898. p. 101) If the condensation of these bodies is furthered by heat, resinous products having a great elasticity are obtained. a

when this condensation takes place in the presence of variable quantities of urea, resins are obtained which differ from resins resulting from the condensation of urea or thiourea with femaldehyde by their chemical composition and their properties.

In particular they are neither gelatinized nor precipitated in concentrated solution by the addition of sulphuric acid of 50% For carrying out the process according to the present invention, the resins above referred to are prepared in the state of aqueous solutions only little condensed (for instance by causing the reagents to act on one anotherin the cold state) and diluted in such manner as to obtain a suitable concentration, which varies with the nature of the fabrics to be treated and of the final-effect to be obtained. This concentration may range between 10 and 30 per cent. Colouring materials, fillers, plastifiers or softening matters may be eventually added to the solutions, and the fabric is. immersed into the bath while suitably stirring it.

It should be noted that interesting results are obtained by making use of the products of the simple condensation of formaldehyde with ammonium sulphides or ammonium suiphocyanide, for instanceby' impregnating a fabric of viscose silk, or copper silk, with a solution containing 100 parts of formaldehyde of 30%, 50 parts of ammonium suiphocyanide and 50 parts of water and by heating in a closed vessel at a temperature of, 80 C. for an hour the fabric freed from the excess of liquid, and then completing polymerization through the action' of heat or by immersing the fabric in a bath of formaldehyde containing 40% the present invention are Y K or by heating in the presence of ammonium suiphocyanide. while, 1 in the case of. urea-formaldehyde, or this-ureaformaldehyde resins, an instantaneous precipi-' ,tation takes place.

in volumes of formaldehyde, removing the excess of liquid from the fabric, dipping in a bath of ammonium sulphide of 30% containing 10% of ammonium suiphocyanide, then removing the excess of liquid from the fabric, drying and polymerizing through the action of heat.

However the best results for practical purposes are obtained with resins resulting from the condensation of formaldehyde with ammonium sulphides or ammonium suiphocyanide in the presence of urea, some properties of which condensation products have been stated above.

In any case, the final polymerization of the resin with which the fabric has been treated is performed through the action of heat at a tem- 15 perature which may range between 70 and 160 C., for instance by causing the fabric to pm over heated cylinders.

In the processes above cited, which makeuse of condensation products of urea, it is necessary, in order to obtain polymerization, to treat either for am an hour at a temperature of. 130 or for several minutes at a temperature of 160-l80 C.

Now, if the polymerizing treatment is to last for half an hour it is very difficult to work in a continuous fashion and if this treatment is to take place at temperatures ranging between 160 and 180 C., the properties of the fabric are very much altered.

n the contrary, according to the present invention, the same degree of polymerization is fabric thus obtained has a very good feel and resists rumpling.

Example II.A fabric is impregnated with a solution containing 500 parts of formaldehyde of 30% in weight, 150 parts of urea, 300 parts of ammonium sulphide of 30% and 2000 parts of water. The fabric is freed from the excess of water and then dried for ten minutes at a temperature of 150 C.

I Example [IL-A viscose fabric is impregnated in a solution containing 900 parts of formaldehyde of 30%, 300 parts of urea, 150 parts of ammonium sulphide of 30%, 1000 parts of water, parts of sulphonated cetyl alcohol, 50 parts of ammonium suiphocyanide, and 20 parts of pure azol blue. The fabric is then treated as in Example II.

Example IV.-The fabric is impregnated as in Examples I and II, then freed from the excess of water and dried. It is then caused to pass over smooth cylinders heatedat a temperature of 100 C., Finally polymerization of the resin is completed by causing the fabric to pass on engraved cylinders heated at a temperature of 150 C. The dressed and goifered fabric thus obtained is capable of resisting flattening and rumpling actions.

What I claim is:

1. The process of treating woven or knitted cellulosic textile fabrics to enable them to resist creasing and rumpling while retaining their flexibility, which comprises the steps of impreggroup consisting of ammonium sulphides andammonium sulphocyanide, and then polymerizingthecondensation product impregnated in the fabric by heating the impregnated fabric to a temperature of between and 160 C.

2. The process of treating woven or knitted cellulosic textile fabrics to enable them to resist.

creasing and rumpling while retaining their flexibilit'y, which comprises the steps of impregnating such fabric in aqueous solution in the cold state, with a soluble condensation product resuiting from the reaction of formaldehyde with a sulphur containing ammonium salt of the group consisting of ammonium sulphides and ammonium sulphocyanide in the presence of urea, and then polymerizing the condensation product impregnated in the fabric by heating the impregnated fabric to a temperature of between C. to 150 C. for a period'of not over ten minutes.

3. The process of treating woven or knitted cellulosic textile fabrics to enable them to resist creasing and rumpling while retaining their flexibility, which comprises the steps of impregnating such fabric in aqueous solution in the cold state, with a soluble condensation product resulting from the reaction of formaldehyde with ammonium sulphide, and then polymerizing the condensation product impregnated in the fabric by heating the impregnated fabric to a temperature of between 100 C. to 150 C. for a period of not over ten minutes.

4. The process of treating woven or knitted cellulosic textile fabrics to enable them to resist creasing and rumpling while retaining their flexibility, which comprises the steps of impregnating such fabric in aqueous solution in the cold state, with a soluble condensation product resulting from the reaction of formaldehyde with ammonium sulphocyanide', and then polymerizing the condensation product impregnated in the fabric by heating the impregnated fabric to a temperature of between 100 C; to 150 C. for a 5 period of not over ten minutes.

5. The continuous process of treating woven or knitted cellulosic textile fabrics to enable them to resist creasing and rumpling while retaining their flexibility, which comprises passing the fab ric in the cold state through a bath which consists of a substantially neutral aqueous solution of a soluble condensation product resulting from the reaction of formaldehyde with a sulphur containing ammonium salt of the group consisting l of ammonium sulphides and ammonium sulphocyanide in the presence of urea, removing excess liquid from the fabric, drying it, and polymerizing the condensation product impregnated in the fabric by continuously subjecting succes- 20 sive portions of the impregnated fabric to a temperature of from approximately C. to C. for from approximately 1 to 2 minutes.

6. The continuous process of treating woven or knitted cellulosic textile fabrics to enable them to resist creasing and rumpling while retaining their flexibility, which comprises passing the fabric in the cold state through a bath which consists of a. substantially neutral aqueous solution of a soluble condensation product result- 30 ing from the reaction of formaldehyde with a sulphur containing ammonium salt of the group consisting of ammonium sulphides and ammonium sulphocyanide in the presence of urea, removing excess liquid from the fabric, drying 35 it, continuously passing the fabric over smooth cylinders heated to approximately 100 C. and then completing the polymerization by passing the cloth over cylinders heated to approximate- 0 PIERRE MEUNIER. 

